1. Field of the Invention
The present invention deals with the use of certain novel polyesters which are prepared by the sequential reaction of castor oil with isostearic acid to provide an intermediate that is subsequently esterified with a diacid to provide a polyester. In addition, the present invention describes a process for providing gloss to the skin which comprises application of an effective glossing concentration of this polyester.
2. Description of the Art Practices
There is a desire to develop an ester that gives gloss to the skin when applied from oils or applied from emulsions. An added aspect of the present invention is the fact that the compounds are polymeric. This has two very important implications on the use of the materials of the present invention. The polymeric nature means the compounds do not penetrate the skin. The fact that these molecules remain on the skin, increases gloss and provides a less irritation to the skin. They also provide a gloss that is more long lasting.
U.S. Pat. No. 5,786,389 issued Jul. 1998 to O""Lenick, incorporated herein by reference, describes the use of a guerbet ester of castor for gloss. The compounds are a simple ester made by the reaction of castor and a specific mono functional alcohol to produce an ester. The products of this patent are neither polymeric, nor do they involve reaction of the hydroxyl group in the castor molecule. We have discovered that higher gloss, lower irritation and better durability of gloss results when one makes the polymers of the present invention.
Until the compounds of the present invention polyesters did not give a sufficient gloss when applied to the skin. None of the prior esters possess the critical combination of branching and the polymeric composition unique to castor.
This invention relates to a series of polyester compounds derived from castor oil. Castor oil, a hydroxy containing oil, can be esterified with a fatty acid to produce an intermediate having both an ester and triglyceride functionality. By selecting the ratios of reactants, the castor can be a partially substituted with fatty acid leaving some unreacted hydroxyl groups. The number of remaining hydroxyl groups, and the type and concentration of diacid used to react with the unreacted hydroxyl groups, results in a controllable polyester. The control of molecular weight and degree of polymerization is critical to functionality of the product.
The unique structure of castor oil coupled with the proper selection of the fatty acid and diacid chosen to make the polyester results in a product that has unique gloss when applied to skin. One of the unique aspects of the present invention is the fact that the reaction to make an ester is conducted on the castor hydroxyl group, not the triglyceride group. Another unique aspect of the present reaction is the selection of a proper mole ratio to leave unreacted hydroxyl groups present in each triglyceride to crosslink the product, providing a polyester.
Specifically, the present invention discloses novel polyesters and a process for providing gloss to the skin which comprises application of an effective glossing concentration of an polyester conforming to the following structure:
Axe2x80x94(B)x-A
wherein
A is: 
wherein;
the linking group between all of the Oxe2x80x94 are succinyl groups conforming to the following structure xe2x80x94C(O)xe2x80x94CH2CH2xe2x80x94C(O)xe2x80x94;
R is selected from alkyl and alkylene having 5 to 33 carbon atoms;
x is an integer ranging from 1 to 50.
In a simple case where x is 1 the following polymer results: 
By varying the ratio of fatty acid more of the hydroxyl group is left. In the case of the xe2x80x9cAxe2x80x9d unit, two of the three hydroxyl groups on the castor oil are reacted, leaving only one group left to react. In the case of the xe2x80x9cBxe2x80x9d units two hydroxyl groups are left to react. In making a one pot synthesis, the total number of acid groups is calculated any reacted in the first step with the castor oil, followed by the reaction of the remaining hydroxyl groups with diacid. In some instances it is desirable to leave some unreacted hydroxyl groups in the polymer.
In a preferred embodiment x is an integer ranging from 3 to 5.
In a preferred embodiment x is an integer ranging from 5 to 10.
In a preferred embodiment R is alkylene having 11 to 21 carbon atoms.
In a preferred embodiment R is alkyl having 7 to 10 carbon atoms.
In a preferred embodiment R is alkylene having 17 carbon atoms.